65岁以上每晚睡7到8小时就够：疾控中心的睡眠时长表与睡个好觉的六个习惯
年纪大了到底该睡多久，美国疾病控制与预防中心（CDC）的「关于睡眠」页面有一张按年龄分的表：18到60岁每晚至少7小时，61到64岁7到9小时，65岁以上7到8小时。长者需要的睡眠只比中年人略少，并不是传言里那样越老越不用睡。
睡够的好处，CDC 列得很实在：少生病、保持健康体重、减压和改善情绪、护心护代谢，并降低2型糖尿病、心脏病、高血压和中风等慢性病的风险，注意力和记忆力也会更好，车祸风险更低。
睡个好觉靠习惯。CDC 给的做法是：每天同一时间上床和起床；卧室保持安静、放松、温度凉爽；睡前至少30分钟关掉电子设备；睡前避免大吃大喝和饮酒；下午和晚上避免咖啡因；白天规律运动、保持健康饮食。
CDC 还提醒，睡够时长不等于睡得好。入睡困难、夜里反复醒、睡满时长白天还是困，都是睡眠质量差的信号；失眠、不宁腿综合征、发作性睡病和睡眠呼吸暂停是常见的睡眠障碍。长期睡不好要去看医生，医生可能会让你记一份睡眠日记，把上床、夜醒、起床、小睡、运动、喝酒和喝咖啡、用药的时间都记下来，帮助找出问题出在哪。（来源：美国疾病控制与预防中心）
Seven to Eight Hours Is the Target After 65: CDC's Sleep Table by Age and Six Habits for Better Sleep
How much sleep an older adult needs is set out in the age table on the Centers for Disease Control and Prevention (CDC) About Sleep page: at least 7 hours a night for ages 18 to 60, 7 to 9 hours for ages 61 to 64, and 7 to 8 hours for adults 65 and older. Older adults need only slightly less sleep than middle-aged adults, not the far smaller amount that is often assumed.
CDC lists what enough sleep does: getting sick less often, staying at a healthy weight, reducing stress and improving mood, better heart health and metabolism, a lower risk of chronic conditions such as type 2 diabetes, heart disease, high blood pressure and stroke, a lower risk of motor vehicle crashes, and better attention and memory.
Good sleep is built on habits. CDC's list is to go to bed and get up at the same time every day, keep the bedroom quiet, relaxing and cool, turn off electronic devices at least 30 minutes before bedtime, avoid large meals and alcohol before bed, avoid caffeine in the afternoon or evening, and exercise regularly while maintaining a healthy diet.
Hours are only half of it, CDC notes. Trouble falling asleep, repeatedly waking during the night, and feeling sleepy even after enough hours are signs of poor sleep quality, and common sleep disorders include insomnia, restless legs syndrome, narcolepsy and sleep apnea. Anyone who regularly has problems sleeping should talk to a health care provider, who may ask for a sleep diary recording bedtimes, night waking, morning waking, naps, exercise, alcohol and caffeine, and medications. (Source: Centers for Disease Control and Prevention)
来源：美国疾病控制与预防中心
发布：GSM·美国（发布链接）
图片来源：图：一位长者在公园长椅上撑伞小憩（资料图）。Wikimedia Commons 图片。 / Photo: An older adult resting on a park bench under an umbrella (file photo). Image via Wikimedia Commons.
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